Wall Street big shots and political insiders yesterday blasted New York Sen. Chuck Schumer for failing to defend the financial industry against Democrats’ attacks and a regulatory crackdown.

Some said they believed Schumer was throwing the city’s largest industry under the bus to ingratiate himself with fellow Democrats and advance his quest to become Senate majority leader if Harry Reid (D-Nev.) is defeated in November.

Others groused that Schumer, a one-time champion of The Street, simply had become President Obama’s lapdog.

“I don’t think there’s any doubt that Chuck will put his personal ambitions — his desire to become majority leader — first when it comes to dealing with Wall Street. And if that means siding with the left wing of our party against the New York economy, he’ll do it,” a prominent Democrat confided to The Post.

A Wall Street hedge-fund manager said: “Schumer is just throwing New York to the wolves.”

“His absence is ridiculous,” a top bank executive added.

“He’s always saying to me, ‘I’m working behind the scenes.’ Well, we don’t need you behind the scenes. We need you out in front of this, Chuck.”

An industry lobbyist said, “There’s a lot of skullduggery here. Schumer doesn’t want to get caught between the White House, which is spoiling for a fight [against Wall Street], and his colleagues.

“[Senate] leadership politics are in play. So he’s taking a dive.”

Schumer said he’s just doing his job.

“The financial industry did things — many wrong — that helped cause the economic crisis and my job now is to help fix them in a way that is corrective, not vindictive,” he said in a written statement.

“Most New Yorkers, both on and off Wall Street, understand that.”

Kathryn Wylde, president of the Partnership for New York City business group, credited Schumer with “fighting very hard” for the industry in private meetings.

She also noted he is “realistic” about the inevitability of reform measures.

Mayor Bloomberg has grown increasingly frustrated by New York Democrats giving in to the populist rage against Wall Street.

Bloomberg had to personally visit the Capitol Monday to warn that higher taxes and crippling regulation could drive financial firms out of the city or out of business altogether — depriving the city of vital jobs and tax revenues.

About 600,000 people in the New York metropolitan region work in the financial sector, according to the US Department of Labor.